991554617 has 4 divisors (see below), whose sum is σ = 992686116. Its totient is φ = 990423120.

The previous prime is 991554611. The next prime is 991554643. The reversal of 991554617 is 716455199.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 921061801 + 70492816 = 30349^2 + 8396^2 .

It is a cyclic number.

It is not a de Polignac number, because 991554617 - 2²² = 987360313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991554611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 564434 + ... + 566187.

It is an arithmetic number, because the mean of its divisors is an integer number (248171529).

Almost surely, 2^991554617 is an apocalyptic number.

It is an amenable number.

991554617 is a deficient number, since it is larger than the sum of its proper divisors (1131499).

991554617 is a wasteful number, since it uses less digits than its factorization.

991554617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1131498.

The product of its digits is 340200, while the sum is 47.

The square root of 991554617 is about 31488.9602400587. The cubic root of 991554617 is about 997.1769099960.

The spelling of 991554617 in words is "nine hundred ninety-one million, five hundred fifty-four thousand, six hundred seventeen".